Semiconductor devices are developed toward a direction with a higher device density and a higher integration level. A transistor is one of the most fundamental semiconductor devices and is widely used. As the device density and the integration level in the semiconductor device increases, critical dimensions of transistors decrease. As the critical dimensions of the transistors decrease, the number of the semiconductor devices on a chip increases, and a distance between adjacent semiconductor devices decreases gradually.
In an epitaxial growth process, a single crystalline layer according to certain requirements is grown on a single crystal substrate, and the single crystalline layer has a crystalline orientation same as the single crystal substrate. The epitaxial growth process is a fundamental growth technology in the semiconductor fabrication technology, and has important applications in forming single crystals. The epitaxial growth process is widely used to form a cathode and an anode of a diode, and source/drain doped regions in metal-oxide-semiconductor (MOS) transistors.
However, performances of semiconductor structures formed by the epitaxial growth process still need to be improved. The disclosed devices and methods are directed to at least partially alleviate one or more problems set forth above and to solve other problems in the art.